RELATED APPLICATIONS
This application is related to this applicant's allowed applications, Ser. No. 07/917,000 now U.S. Pat. No. 5,285,586, filed Jun. 26, 1992, and Ser. No. 08/013,839, filed Feb. 5, 1993, now U.S. Pat. No. 5,303,485, the disclosures of which, by this reference, are incorporated herein in their entireties.
1. Field of the Invention
This invention pertains to lighted footwear in general, and in particular, to footwear having lights that flash on and off periodically in response to inertial forces acting on the footwear, such as those incident on the footwear when it impacts against the ground.
2. Description of the Related Art
The provision of lights in shoes and boots to achieve a variety of utilitarian or novelty effects is well known in the footwear art. Typical offerings comprise one or more small sources of electrical light, e.g., incandescent bulbs, neon tubes, or light-emitting diodes ("LED's"), a small portable power source, such as a dry-cell battery, and some electrical circuitry to connect the power source to the light sources electrically, which circuitry usually includes some means for switching the light sources on and off in a desirable fashion.
In some cases, this switching function is achieved by the provision of a simple, manually-actuated on/off switch on the footwear, such as are to be found in the lighted sandal described by B. Arias, et al., in U.S. Pat. No. 2,931,893, and the lighted, detachable heel described in U.S. Pat. No. 4,253,253 to A. McCormick. While these systems are simple and inexpensive to implement, they do not provide a very dynamic light display or one that is interactive with the wearer's activities, such as would be achieved by a lighting system that is operatively responsive to, say, movement of the footwear, or its impact upon, or departure from, the ground. Also, since the lights are continuously "on" until switched "off" manually, rapid battery exhaustion can be a problem.
Numerous examples of efforts made to overcome one or both of these problems may be found in the patent literature. For example, each of the following patents describes a variant of lighted footwear in which a displacement-actuated switch is disposed above, within, or below the sole of the footwear, frequently in the heel, to switch the lights on when the footwear is in contact with the ground, and to switch them off when it is not: U.S. Pats. No. 1,933,243 to J. De Merolis, et al.; U.S. Pat. No. 3,008,038 to M. Dickens, et al.; U.S. Pat. No. 3,070,907 to J. Rocco; U.S. Pat. No. 3,800,133 to H. Duval; U.S. Pat. No. 4,014,115 to R. Reichert; U.S. Pat. No. 4,128,861 to A. Pelengaris; and U.S. Pat. No. 4,130,951 to A. Powell. While these systems all generally provide a more dynamic mode of light actuation, they also all share a common problem, namely, relatively quick battery depletion, since the lights in the footwear are continuously "on" while the footwear is in contact with the ground, such as occurs in activities involving much standing.
In U.S. Pat. No. 2,572,760, N. Rikelman describes a lighting device for footwear that clips over the instep of a shoe or boot. In one of the embodiments illustrated, the switching function of the incandescent light is achieved by a ball bearing disposed inside of a tube to roll randomly, with movement of the footwear, into and out of engagement with an electrical contact to switch the light on and off.
In U.S. Pat. No. 5,052,131, P. Rondini describes a sandal having an oscillator circuit that is actuated by means of a displacement switch in the heel of the sandal to cause the light sources in the sandal's straps to flash on and off periodically. This flashing actuation of the lights not only provides a more dynamic light display, but can also prolong battery life, depending on the "duty cycle" of the oscillator circuit.
In this applicant's above-referenced copending application, Ser. No. 08/013,839, filed Feb. 5, 1993, variants of footwear lighting systems are described in which the lights are switched on whenever the wearer's foot leaves the ground, and are switched off when the wearer's foot is in contact with the ground. While these systems are also relatively more dynamic in appearance and can provide prolonged battery life, some additional switching means are necessary to switch the lights off when the wearer's foot is off the ground for an extended time, such as when the wearer sits with a leg crossed.
In U.S. Pats. Nos. 3,893,247 and 4,158,922, A. Dana III describes lighted footwear in which the lights are connected to, or disconnected from, the battery by means of a mercury switch mounted in the footwear, which makes or breaks the battery-light connection in response to the position of the switch relative to the gravity gradient. In the latter reference, an optional oscillator circuit is described which causes the lights to flash on and off periodically when the mercury switch is in the "on" position, and an optional battery charging circuit can be included to re-charge a depleted battery. It may be seen that, while both of these systems can provide a more dynamic lighting effect and extended battery life, the actuation, and "on" period itself, of the lights can be unpredictable and is highly dependant on the mounting attitude of the mercury switch in the footwear.
In U.S. Pat. No. 4,848,009, N. Rodgers describes lighted footwear in which a mercury switch is used in a manner similar to the two references described above to trigger an integrated "timing" circuit, which in turn, turns the lights in the footwear on for a predetermined period of time, then turns them off again, and keeps them turned off until the mercury switch is first opened, then closed again. Although relatively more complex, from an electronics standpoint, this system provides a satisfactory dynamic lighting effect, along with an extended battery life, due primarily to the fact that the predetermined period of time during which the lights are "on" can be set to be relatively brief, such that the "on" period corresponds to a brief "flash" of the lights.
In U.S. Pat. No. 5,188,447, L. Chiang, et al., describe a lighted footwear system in which the lights are actuated by the impact of the footwear against an object, such as the ground. In this system, a piezoelectric crystal operates as a voltage generator to generate a brief voltage pulse, the amplitude of which is related to the amount of inertial force incident upon the crystal. The voltage pulse is used as the input of a battery-driven amplifier, which, in turn, drives the lights, such that the intensity of the single pulse of light emitted by the lights is related to the mount of force with which the footwear impacts the object. Like the Rodgers system described above, this lighting system provides a dynamic, interactive lighting response, and is relatively conservative of battery life, but is also relatively more complex and expensive to implement in low-cost footwear.
The present invention relates to lighted footwear in which the lights are actuated by an improved switching mechanism that is responsive to inertial forces acting on the footwear, such as those incident on the footwear when impacting the ground or kicking a ball, to cause the lights to flash on and off periodically for only a very brief period, thereby providing a relatively dynamic, interactive lighting effect, while achieving a relatively long battery life. This novel system is achieved in a design that is very simple and reliable in its operation, inexpensive to manufacture, small and lightweight, and therefore, ideal for incorporation into footwear.